The present invention relates to a propylene resin composition which is superior in all of the following properties concurrently: rigidity, heat resistance, impact resistance, surface hardness, etc.; and which is suited for use in machine parts, electric and electronic parts, packaging materials, engineering plastic substitutes, etc.
2. Background Art
Polypropylene is widely used, for example, in industrial materials for vehicle parts, electric and electronic parts, etc., and in various packaging materials, since it is generally inexpensive, and has the advantages of light-weight characteristics, mechanical strength, heat resistance, chemical resistance, etc.
In recent years, there has been a strong demand for improvements in quality along with increased functionality and reduced costs for these materials.
As ways to improve the rigidity, impact resistance, heat resistance, etc., of polypropylene, methods have been proposed such as incorporating an ethylene-propylene rubber and a nucleating agent into an ethylene-propylene block copolymer (Japanese Patent Application, Second Publication, No. Sho 60-3420), and incorporating an ethylene-propylene rubber, an ethylene copolymer, and an inorganic filler into an ethylene-propylene block copolymer (Japanese Patent Application, First Publication, No. Hei 4-275351, Japanese Patent Application, First Publication, No. Hei 5-5051, Japanese Patent Application, First Publication, No. Hei 5-98097, Japanese Patent Application, First Publication, No. Hei 5-98098).
However, in the above-mentioned methods, although some characteristics have been improved, heat resistance and rigidity still have not been adequately improved.